Compound pipe or tube.



.No. 798,056. Y PATBNTED AUG. 22, 1905. J. H. NICHOLSON. comronun PIPEon TUBE.

APPLICATION FILED JUIIE 10,1904.

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terior of the tube. considerable thickness, the electroplating of UNITEDSTATES PATENT OFFIC 1 JOHN H. NICHOLSON, OF PITTSBURG, PENNSYLVANIA,ASSIGNOR TO NATIONAL TUBE COMPANY, OF PITTSBURG, PENNSYLVANIA, A

CORPORATION OF NEIV JERSEY.

COMPOUND PIPE OR TUBE.

Specification of Letters Patent.

Patented Aug. 22, 1905.

To all wit/mt it may concern:

Be it known that I, JOHN H. NICHOLSON, of Pittsburg, Allegheny county,Pennsylvania, have invented a new and useful Compound Pipe or Tube, ofwhich the following is a full, clear, and exact description, referencebeing had to the accompanying drawing, forming part of thisspecification, in which the figure is a longitudinal central section ofa portion of tubing constructed in accordance with my invention.

My invention relates to the manufacture of compound tubing having aninside or outside covering, and particularly to the welding of a nickelcovering either external or internal, or botht0 a steel or iron tube inorder to give a non-corrosive surface, and is designed to provide anarticle having the surfaces so thorough] y welded that when the tube isbent, expanded, or otherwise changed in form there will be no separationbetween the layers.

Heretofore iron or steel tubes have been drawn down upon a thin liningof brass or copper or an external covering of brass or copper has beendrawn down on an iron or steel tube. In this case, however, there is noweld between the metals, and when the tube is changed in form the metalswill separate.

Iron and steel tubes have also been coated by dipping in zinc, tin,lead, 620., and have also been electroplated with copper, nickel, 860.This electroplating can be carried. out successfully in giving anexterior coating; but it is very difficult to electroplate the in-IVhere this coating is of metal is irregular, porous, and brittle, andthe metals are liable to separate when the tube is beaded ormanipulated.

It has also been proposed to weld a copper or brass lining in iron orsteel tubes; but the melting-points of the two metals are so dissimilarthat when this is attempted the copper or brass lining or covering willmelt and run before the iron or steel reaches the welding temperature.Hence there is no substantial weld between the metals in this case, andwhen the tube is changed in form the metals will separate.

I have discovered that I can successfully weld a layer of nickel to aniron or steel tube, either externally or internally, by applying aseamless tube of nickel thereto, protecting the welding-surfaces fromoxidizing influences while heating the nested blank and applyingpressure, whereby a substantial and perfect weld is obtained. Nickel iswell adapted to withstand corrosion and oxidation at ordinarytemperatures. It is of about equal hardness with steel, and thefusing-point of the two metals are near each other.

In attempting to weld nickel to iron by ordinary methods the nickel whenheated absorbs oxygen, which changes the nature of the welding-surfaceand prevents a proper welding; but by nesting the two hollow blanks ofnickel and iron within each other and protecting their welding-surfaceswhile heating I can obtain excellent results.

In carrying out my invention for the manufacture of a nickel-linedboiler-tube I preferably take a pierced-steel billet that has had itsinterior surface pickled or cleaned, so as to remove all scale or oxid,and nest within ita thin seamless nickel tube of the same length as thepierced billet. I then drive tapering plugs into the ends of the nickeltube, expanding the same so that they fit snugly into the ends of thehollow billet and prevent the air and hot gases of the furnace fromcoming in contact with the welding-surfaces of the nickel and steel toany harmful extent. I then place this compound hollow billet or blank ina furnace and heatit to, preferably, about 2,300 Fahrenheit. When theblank is thoroughly heated to this temperature, it is withdrawn from thefurnace and passed through angularly-disposed rotating rolls or disksand over an interior supporting-rnandrel, giving it a high rotary speedand at the same time a forward motion over the mandrel, subjecting allportions of the billet to a great pressure, reducing the thickness ofwall, and elongating the billet. For this operation I preferably use theapparatus of United States Patent No. 718,723, dated January 20, 1903,in which a continuous spiral movement and great pressure is impartedwhich is extremely effective in giving a weld. The welded blank thusformed is then placed on a mandrel and at the same heat is reduced indiameter and thickness and elongated by the well-known swaging processused in making seamless steel tubes. This hot rolled tube as it comesfrom the swaging-mill can be further reduced in diameter and thicknessof wall, if so desired,

by the usual method of cold-drawing as well understood by those versedin the art. .In

this step the wall thickness of the nickel and the steel is reducedproportionately and the compound tube draws like one solid piece ofmetal, the weld being so perfect that the line of unison of the twometals cannot be detected without etching with acid, the color of thenickel and steel being alike.

In the figure, 2 represents the steel body of the tube, and 3 theseamless nickel tube-lining, which is thoroughly welded theretothroughout its length.

The ad vantages of my invention will be ap preciat'ed by those skilledin the art. A tube having a seamless lining of nickel welded to an ironor steel body is formed which presents the advantages of a solid nickeltube without its high cost. The method of securing the weld between thenickel and steel is peculiarly adapted to the usual method ofmanufacturing seamless tubes. No new apparatus of any kind is required,as the cross-rolling device used for securing the weld is the same as isused for the production of the pierced-steel billets, and the subsequentrolling devices for elongating the welded blank are the same as used formaking'the seamless steel tubes. The nickel tubes for lining andcovering are made in an identical manner as the steel tubes. The onlydifference in making the steel tubes and the nickel-lined ones is theduplicating of several of the different operations. The article producedis of high quality, as the weld is substantially perfect throughout andthe metals will not separate when the tube is beaded or otherwisechanged in form. I

The protecting of the Welding-surfaces of the hollow blanks is of greatimportance, as'it enables me to obtain the complete weld between theblanks. The small amount of air between the blanks does not preventitswelding, and during the heating the inner surface of the thick steelblank contracts, while the inner finished nickel blank expands, thusbringing the welding-surfaces closer together.

The invention may be used for the welding of steel or iron to an alloyof nickel, the same being nested and treated as before described. It mayalso be used for welding other dissimicountof the oxidizing 'or changein the nature of the welding-surfaces, due to contact with the hot gasesof the furnace. Instead of expanding the ends of the thin tube the tubesmay be nested together so closely as to practically excludetheioxidizing-gases.

Iemay also take the pierced billet as it comes in its heated conditionfrom the piercing-mill before it has had time to materially oxidizewithin it and thenpass the compound blank through a circularrolling-mill pass,which will roll the pierced steel blank down onto thelining-tube. This will prevent the oxidizing of the welded surfacesduring the heating of the compound blank.

In applying the external cover to the pierced blank I may heat thecover, slip it on the hot pierced blank before scale has formed on itscircular rolling-mill pass, thus bringing the surfaces closely togetherand preventing the oxidizing action, so'that both surfaces are inexcellent shape.

The apparatus employed may be changed and many other changes may be madewithout departing from my invention.

By the term iron used in the claims I intend to include iron, steel, andalloys thereof, and by the term nickel I intend to include not only purenickel, but alloys of'nickel in which the nickel predominates.

I claim 1. As a new article of manufacture, a compound tube or pipehaving an iron or steel body and a nickel tube welded thereto;substantially as described.

2. As a new article of manufacture, a compound tube or pipe having aniron or steel body and a seamless nickel tube welded thereto;substantially as described.

3. As a new article of manufacture, a compound tube or pipe having aseamless iron or steel body and a seamless interior nickel tube weldedthereto; substantially as described.

In testimony whereof I have hereunto set my hand.

JOHN H. NICHOLSON. Witnesses:

JOHN MILLER,

lar metals or alloys thesurfaces of which can- H\ M. CoRWIN.

not be welded by ordinary methods on ac- I on its inner surfaces andslip the lining-tube exterior, and'then pass the blank through a

